0.9999.... = 1.0

[dsgrue3]

pezus said:

dsgrue3 said:
x = 2
x^2 = 4
x = +/- 2

Fuzzy math is fuzzy. This is why it doesn't sit well with me.

I understand it through Pezus' example with fractions, but this isn't an equation. It's just an assertion.

It isn't a proof at all.

Surely you admit -2 != 2?

Where is this equation and who are you replying to? o.O

I'm showing the OP and others that you can manipulate values willy nilly and it isn't a proof.

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x = 0.9999…	given
10x = 9.9999….	multiply by 10
9x = 9	subtract x
x = 1	divide by 9
0.999... = 1	substitution

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This was his  "proof"

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x = 2	given
x^2 = 4	square both sides
x = +/- 2	take sqr root
-2 = 2	substitution

- 

It is invalid. I'm pretty sure in order for you to do this you need an equation which resolves to 0.